NMDS plot of reef fish species abundance community composition (n = 3 / tide / SGD influence / habitat type; stress = .15). Data underwent Hellinger transformation - good for species abundance data, gives low weights to variables with many zeros.
There is a significant difference between fish assemblages in sand habitats and reef habitats (ANOSIM, R = .7025,p =.0001)
Communities in sand habitats are significantly more variable than those in reef habitats (ANOVA / betadisp; F = 17.71, p = .0003)
In sand habitats, there are significant difference in fish assemblages between high and low groundwater influence (ANOSIM, R = .4204, p = .0038).
ANOSIM tests whether two or more groups of samples are significantly
different.
Do significant differences between habitat types mean they can be
analyzed separately can only specify one grouping (I think) & cannot
do interactive effects, how to look at interaction between SGD &
tide?
How to track changes between high and low tide at one site? calculate
distance between points and then group distances?
A significant difference between fish families in sand habitats and
reef habitats (ANOSIM, R: .5667, p=.002)
Kuhliidae are a family of flagtails: most are euryhaline and often found
in brackish water, but the genus also includes species restricted to
marine or fresh water.
A significant difference between fish families in high groundwater vs low groundwater (ANOSIM, R: .1375, p=.0067 ) Not the case for species differences, only families.
Communities in sand habitats are significantly more variable than those in reef habitats (ANOVA / betadisp; F = 49.91, p < .00001)
In sand habitats, there are significant difference in fish assemblages between high and low groundwater influence (ANOSIM, R: .5667, p=.0019)
Species richness is higher in reefs than sand habitats (3 way ANOVA,
F = 17.883, p = .006)
Significant three way SGD:tide:substrate interaction.
No significant relationships because standard deviation too high.
Slight SGD influence (p = .07)
33 species that have observations feeding on plankton in high SGD
regions at low tide